Cas Iron

[Wheels]

Anyone had any success welding cracked engine blocks?

The picture is of a 305 Chevy marine engine block that was frozen and cracked from lack of proper storage. My brother-in-law and I changed it out with a replacement this weekend, but I hate to discard it if it can be repaired.

What procedure would you recomend for repair? Brazing came to mind , but I am quite green when it comes to this type of repair, so any comments would be of use.

We will,of course ,disassemble it to check for any unseen damage.

[boilerman79]

i have had good luck with stick welding cast with eutectic 2240 rods.you must vee the crack and chase it out.[i use dye penatrant] pre heat it and let it cool down slowly.i would suggest you take it to a welding shop if you lack the experence .this is something that you may want to scrap. this is a little different than welding on a tractor or truck block.this could leave you in deep water.

[Paul Seaman]

I have fixed broken blocks on model T's that were only cracked in the water jacket and used Ni99 rod with a groove prep. The Pic looks like the crack is shaped like an H. I would be worried of the possibility that it could be in the oil passage. Also a 2 dimensional crack can recrack near the completion of the last leg of the weld. A post weld treatment would be to keep the temp from falling too fast and causing a crack.

This is tricky work, I would get some old manifolds or another block to practice on before trying a potentially good engine. You know practice makes perfect.

Peace,

[Wheels]

Boilerman
This block proably should be scrapped, but you know how relatives are.I am not concerned about it if there are no internal issues . I would be more leary if it was a car or p-up engine , where a closed system would have pressure and a limited coolant supply. A boat on the other hand has an unlimited supply as long as the water pump is operating and the boat is floating we are good to go.

PJ this might give me a reason to fire up the Dynasty and use the stick side for the first time, might be a hoot!

Thanks Mike

[Paul Seaman]

Education is a very cool thing and its better if you have something to gain but not too much to loose if you fail. Give it a whirl let me know how it comes out. BTW Ni99 is very expensive I rescently bought some and it cost me about $30 per pound.

Good luck,

[RussellH]

I came a cross a couple of links that you might be interested in:

http://www.lincolnelectric.com/knowl...nt/twoguys.asp

http://www.lincolnelectric.com/knowl...ronpreheat.asp

[Wheels]

Thanks a lot Russell, I put the links on my favorites list and will read them before going any further.

Mike

[Tanner]

I've welded cast iron before. One time on a folding brake hinge. Somebody put some 1/8" mild steel in it and tried to bend it. KERSNAP! Oh well. A quick 300°F preheat and one Ni99 rod later, it was fixed. The other time was on a 1930's John Deer tractor part, but we brazed that. I would just braze it...but that's just me.

[jeffscarstrucks]

Check the lifter valley very well before you make a decision, small blocks that have frozen are good for a lot of hard to see damage in that area. JEFF

[timw]

My 2 cents, it's a 305 why bother! They are easy to come by around here. If I had a need for it I would find a 350 short block and use it with my heads. The time spent on the 305 and then to have a problem with it later isn't worth it. The area that it cracked could have caused damage to the cylinders. You need to get it apart and check it with a cylinder bore gage. The GM small block engines I've seen freeze busted cracked on the inside in the valley, just below the head, above the lifter bores.